heirloom-ex-vi VS OpenVi

Using Carsten Kunze's actively maintained continuation of Gunnar Ritter's (outstanding) traditional ex/vi project is highly recommended. See https://github.com/n-t-roff/heirloom-ex-vi/.

The parent project on SourceForge hasn't had any activity for 15 years, nor a release in 17+ years, but still contain various known bugs, all of which are fixed in Carsten Kunze's project.

Attempting this clone of traditional vi from GitHub instead of SourceForge (the SF version lacked libuxre which was available on the GH version), it looks like heirloom ex also cleared the screen, unlike ed(1).

I came across a more recently updated copy of that code which works with modern terminals "out of the box", and includes other bugfixes: https://github.com/n-t-roff/heirloom-ex-vi

The behavior of the traditional vi is much different than vim and other clones. Nvi was a actually a re-implementation of the traditional vi for 4BSD (to be clean of AT&T code) and thus was originally intended to be bug-for-bug compatible, but breaking away where the original vi behavior was nonsensical or terrible.

For vim, `set compatible` or `set cp` is close, but still not traditional vi by any means.

A multibyte variant of the tradition vi is maintained - https://github.com/n-t-roff/heirloom-ex-vi/.

Nvi (now on version 1.8x) is also maintained - https://repo.or.cz/nvi.git

Nvi2 is yet another fork of Nvi, https://github.com/lichray/nvi2

Despite the very similar names, all of these editors have a variety of different features, and are structured very differently.

Nvi has a concept of a front-end and a back-end (which uses the BDB database). OpenVi uses the OpenBSD version of Berkeley DB which derives from 1.85. Nvi (1.8x) provides a minimal version of code also derived from that release intended from use with Nvi, and (IIRC) also provides support for using Db3/4/5. Similar situation for Nvi2.

Nvi 1.8 has been structured where a third library layer has been added, which doesn't exist in OpenBSD's vi or OpenVi. There is scripting support (Tcl, Perl, etc.) and GUI code in the other various forks ... all of these support various different options as well.

I should probably make a matrix of these, but you can get an idea by looking at the settable options implemented in each of the variants (as they historically include a comment to document from where the option originated):

OpenVi: https://github.com/johnsonjh/OpenVi/blob/22c2a7022e31d91e09e...

OpenBSD vi: https://github.com/openbsd/src/blob/master/usr.bin/vi/common...

Nvi2: https://github.com/lichray/nvi2/blob/5fcdc13656500a8c5b4c073...

Nvi1: https://repo.or.cz/nvi.git/blob/HEAD:/common/options.c#l52

OpenVi: Portable OpenBSD vi for Unix systems\ (22 comments)